In the process of packaging material-web rolls, such as paperweb rolls, it is common to initially apply an inner end face cover to each end face of the roll. Thereafter, the material-web roll is circumferentially shrouded by a packaging web which, as a rule, surrounds the roll in several layers and also projects somewhat beyond the roll axially. The axial projections are pleated during or after the shrouding of the roll so that the resulting pleats abut against the end faces. Finally, an outer end face cover is applied to each end face of the shrouded roll and, as a rule, are glued thereto. Such an arrangement or method is known from EPO 499 954 A1, for example. The inner end face cover can be omitted when a suitable outer end face cover is being used as is known from EPO 494 750 A1, for example.
The packaging of a roll not only serves as a mechanical protection against soiling or damaging from the outside. The packaging should also be sufficiently tight so that, by way of example, variations of the humidity of the ambient air do not negatively influence the material-web that has been wound on the roll.
Such relatively tight packaging, however, creates other problems because during the act of packaging and especially when applying the outer end face covers, it is practically impossible to prevent air from being enclosed within the package. The packaging material thereby does not lie uniformly and closely against all surfaces of the roll, especially when air is trapped at the end faces of the roll such as, for example, within the pleats of the axial projections or between the pleats and the roll. Such trapped air can also cause a bursting of the package when depositing the packaged roll on one of its end faces.